Combination pronged base for electrical devices



May 29, 1956 R. FONT ET AL COMBINATION PRONGED BASE FOR ELECTRICALDEVICES Filed Dec. 14, 1955 INVENTORS RAMa/v Fo/vr AND A/vrHo/vy HERMANCOMBINATION PRONGED BASE FOR ELECTRICAL DEVICES Ramon Font, RichmondHill, and Anthony Herman, Queens Village, N. Y., assignors to PremierResearch Laboratories, Inc., New York, N. Y.

Application December 14, 1953, Serial No. 397,824

Claims. (Cl. 317-257) This invention relates to pronged connectors, andmore particularly to a pronged base of the type including a condenserincorporated therein.

A main object of the invention is to provide a novel and'improvedpronged base for use with an electrical unit,'such as a vacuum tube,coil assembly, piezoelectric crystal assembly, or the like, said baseincluding a variable condenser therein, the device being simple inconstruction, being easy to adjust, and being stable in operation.

A further object of the invention is to provide an improved combinationpronged base and variable condenser which is inexpensive to manufacture,which is rugged in construction, and which is compact in size.

A still further object of the invention is to provide an improvedpronged base for an electrical component, said base embodying a trimmercondenser therein which may be readily adjusted to regulate theperformance of the component mounted on the base.

A still further object of the invention is to provide an improvedcombination pronged base and variable condenser which will not besubstantially affected by ambient temperature and humidity variations,which will not be readily shaken out of adjustment by mechanicalvibration, and which will remain in adjusted position over long periodsof time and under severe operating conditions.

Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the acompanyingdrawings, wherein:

Figure l is a vertical cross-sectional view taken through one form ofimproved combination pronged base constructed in accordance with thepresent invention said view being taken on line 11 of Figure 2.

Figure 2 is a top plan view of the pronged base of Figure 1.

Figure 3 is a side elevational View of another form of combinationpronged base according to the present invention.'

Figure 4 is a bottom plan view of the pronged base of Figure 3 with aportion of the protective bottom cover screw broken away.

Figure 5 is an enlarged fragmentary cross-sectional detail view taken online 55 of Figure 2.

Figure 6 is a cross-sectional detail view taken on line 66 of Figure 5.

Referring to the drawings, and more particularly to Figures 1, 2, 5 and6, 11 generally designates a pronged base comprising the main body 12 ofrigid insulating material, provided with the Contact prongs 13. Asshown, the body 12 is formed with respective vertical bores 14communicating with the top ends of the respective contact prongs 13.Said body is also formed with the peripheral groove 15 adapted to belockingly engaged by 'an inwardly extending rim element of the housingmember 16 to be secured on the pronged base. Said housing member maycomprise the outer housing of a vacuum tube, coil assembly,piezoelectric crystal assembly, or

other component to .be mounted on the pronged base.

atent f) 2,748,328 Patented May 29, 1956 The body 12 is centrally formedwith a cylindrical bore 17 extending axially in said body. Disposed insaid bore against the wall thereof is an arcuate plate element 18 ofrelatively thin sheet metal, said plate element extending for the fullheight of bore 17 and being formed at one top corner thereof with aterminal lug 19 which engages the top surface of body 12 and extendsover a vertical bore 14. The lug 19 is electrically connected to theprong 13 associated with said vertical bore 14 by a connecting wire 20.

The plate element 18 is of substantial arcuate extent and preferablyextendsabout halfway around the internal circumference of bore 17.Designated at 21 is a metal rotor block which comprises a main bodysubstantially equal in height to the height of bore 17, said blockhaving an arcuate outer surface 22 which is concentric with bore 17, isslightly smaller in radius than said bore, and which preferably extendsabout halfway around the internal circumference of said bore. Block 21is disposed inside the bore 17 and is integrally formed with an axialpivot stud 23 which is rotatably received in a central aperture 24formed in the bottom wall of bore 17. Stud 23 is provided with a screwdriver groove 25 which is accessible from the bottom of base 11, wherebythe block 21 may be rotatably adjusted at times by engaging a screwdriver blade in the groove 25.

The top surface of block 21 is formed with a conical recess 26 which isaxially located relative to bore 17. Designated at 27 is a resilientcontact arm formed integral with and extending from a terminal element28 secured in one of the vertical bores 14 and electrically connected tothe contact prong 13 associated therewith. The end portion of resilientarm 27 is locally depressed at 29 to define a conical pivot point whichpivotally engages in the conical recess 26 and exerts a retaining forceon the block 21, holding said block in the bore 17, as well asestablishing the electrical connection between the block and the prongassociated with terminal element 28.

Disposed in the bore 17 between block 21 and plate element 18 is a thincylindrical shell 30 of flexible insulating material, such as thinplastic tubing, or the like, which provides a dielectric layer betweenplate element 18 and sector block 21.

As shown, the dielectric shell 30 extends for the full height of bore 17and is retained therein by the overlying contact arm 27.

As shown in Figure 6, the flexible shell 30 fits closely between thearcuate plate element 18 and the arcuate surface of block 21, wherebythere is considerable frictional binding of the shell against thesurface of the block. This serves to hold the block in adjusted positionrelative to the plate element 18. A substantial torque must be appliedto the stud 23 to rotate said block and to vary its adjusted position.It will be further apparent that the capacity between block 21 and plateelement 18 will be directly proportional to the opposing overlappingareas thereof and that said capacity can be varied by rotating saidblock.

The terminal elements 19 and 28 may be electrically connected to theelectrical component mounted on the base 11 by suitable relatively shortwires in the housing 16, whereby the condenser may be connected directlyto the component without requiring external connections, thus minimizingundesired load capacity. In the case of a coil or piezoelectric crystalassembly, frequency adjustments may be made directly without requiringthe use of an external padding or trimmer condenser. Similarly, adesired value of capacity may be applied directly between the lead wiresof the elements of a vacuum tube assembly mounted on base 11 withoutrequiring the use of an external trimmer-condenser.

In the form of the invention illustrated in Figures 3 w and 4, thebase,shown at "11', is of the octal type and is provided with the hollowcentral depending key member 31 l aving the aligning rib 32. A removablecover screw 33 is threadedly engaged in the bottom of the key member 31.The capacity adjusting stud 23 is accessible through the hollow keymember 31 by removing the screw 33, whereby the blade of a screw drivermaybe inserted through the key member 31 to engage the groove 25 in stud23. After the desired capacity adjustment is made, the screw 33 may bereplaced to seal the key member 31 against the entry of moisture orother undesired foreign material. As in the previously described form ofthe invention, the terminalelements 19 and 27 are electrically connectedto respective contact prongs, shown at 13', of the base 11.

The condenser is also protected against rapid fluctuations in ambienttemperature, since the elements thereof are substantially completelyenclosed by material having low heat conductivity, and also because theblock 21 is of substantial mass, whereby its thermal capacity isrelatively large, preventing rapidfluctuations .of its temperature andpreventing rapid fluctuations of the temperature inside the bore 17;

While certain specific embodiments of combination pronged bases andcondensers have been disclosed in the foregoing description, it will beunderstood that various modifications within the spirit of the inventionmay occur to those skilled in the art. Therefore it is intended that nolimitations be placed on the invention except as defined by the scope ofthe appended claims.

What is claimed is:

1. In an electrical device, a base member, a plurality of prongs rigidlysecured to said base member and adapted to be electrically connected tothe device, said base member being formed with a cylindrical recess, thebottom wall of said recess being formed with a central aperture, anarcuately curved conductive plate element disposed in said recessadjacent the wall thereof and defining one plate of a condenser, aconductive rotor block rotatably mounted in said recess, said blockhaving an arcuate surface located adjacent said plate element, saidarcuate surface being in capacitive relation to said plate element,means connecting said plate element to one of the prongs, a resilientarm connected to another prong and pivotally engaging the top of theblock at a point axially located relative to the recess, dielectricmeans disposed between the arcuate surface of the block and-said plateelement, and an axially extending stud element on the bottom of saidblock extending into said central aperture, whereby it may be engagedfrom below the base memb r to rotate the block and adjust the capacityof said condenser.

2. In an electrical device, a base member, a plurality of prongs rigidlysecured to said base member and adapted to be electrically connected tothe device, said base member being formed with a cylindrical recess, thebottom wall of said recess being formed with a central aperture, anarcuately curved plate element disposed in said recess adjacent the wallthereof and defining one plate of a condenser, a conductive rotor blockrotatably mounted in said recess, said block having an arcuate surfacelocated adjacent said plate element, said arcuate surface being incapacitive relation to said plate element, a sleeve element of thinflexible dielectric material surrounding said block and having a portionthereof disposed between the arcuate surface of the block and said plateelement, and a stud elementon said block extending into said centralaperture, whereby it may be engaged from below the base member to rotatethe block and adjust the capacity of said condenser.

33. In an electrical device, a base member, a plurality of prongsrigidly secured to said base member and adapted to be electricallyconnected to the device, said base member being formed with acylindrical recess, the bottom wall of said recess being formed with acentral aperture, an arcuately curved conductive plate element disposedin said recess adjacent the wall thereof and defining one plate of acondenser, a conductive rotor block rotatably mounted in said recess,said block having an arcuate surface located adjacent said plateelement, said arcuate surface being in capacitive relation to said plateelement, means connecting said plate element to one of the prongs, aresilient arm connected to another prong and pivotally engaging the topof the block at a point axially located relative to the recess, a sleeveelement of thin flexible dielectric material surrounding said block andhaving a portion thereof disposed between the arcuate surface of theblock and said plate element, and an axially extending stud element onthe bottom of said block extending into said central aperture, wherebyit may .be engaged from below the base member to rotate the block andadjust the capacity of said condenser.

4. In an electrical device, a base member, a plurality of prongs rigidlysecured to said base member and adapted to be electrically connected tothe device, said base member being formed with a cylindrical recess, thebottom wall of said recess being formed with a .central aperture, anarcuately .curved conductive plate element disposed in said recessadjacent the Wall thereof and defining one plate of a condenser, aconductive rotor block rotatably mounted in said recess, said blockhaving an arcuate surface located adjacent said plate element, saidarcuate surface being in capacitive relation to said .plate element,dielectric means comprising flexible dielectric material disposedbetween the arcuate surface of the block and said plate element, a studelement on said block extending into said central aperture, whereby itmay be engaged from below thebase member to rotate the block and adjustthe capacity of said condenser, a depending hollow key member rigidlysecured to said base member coaxially with said stud element, and aclosure member detachably secured in the bottom end of said key memherfor protecting the key member against the entry of foreign material.

5. In an electrical device, a base member, a plurality of prongs rigidlysecured to said base member and adapted to .be electrically connected tothe device, said base. member being formed with a cylindrical recess,the bottom wall of said recess being formed with a central aperture, anarcuately curved conductive plate element disposed in said recessadjacent the wall thereof and defining one plate of a condenser, aconductive rotor block rotatably mounted in said recess, said blockhaving an arcuate surface located adjacent said plate element, saidarcuate surface being in capacitive relation to said plate element,means connecting said plate element to one of the prongs, a resilientarm connected to another prong and extending over the top surface of theblock, said top surface being formed with a pivot recess located axiallyrelative to said first-named recess, a depending pivot element on saidarm engaged in said pivot recess, dielectric means disposed between thearcuate surface of the block and said plate element, and an axiallyextending stud element on the bottom of said block extending into saidcentral aperture, whereby it may be engaged from below the base memberto rotate the block and adjust the capacity of said condenser.

References Cited in the file of this patent UNITED STATES PATENTS1,683,202 MacDonald Sept. 4, 1928 1,825,534 Mayrogenis Sept. 29, 19311,871,048 Dubilier Aug. 9, 1932 1,930,523 .Landon Oct. 17, .19332,030,271 Schaper Feb. 11, .1936 2,488,791 Zaat Nov. 22, 1949 2,532,836Cupido Dec. 5, 1950 2,556,453 Sperry June 12, 1951 2,618,749 AltenbergerNov. 18, 1952

